Increased expression of immunoglobulin is a characteristic of many diseases. High level secretion of immunoglobulin causes a variety of disorders, including hyperviscosity syndrome, a debilitating disorder resulting in fatigue, headaches, shortness of breath, mental confusion, chest pain, kidney damage and failure, vision problems and Raynaud's phenomenon (poor blood circulation, particularly fingers, toes, nose and ears). Cold agglutinin disease, mixed cryoglobulinemia, hypergammaglobulinemia, Sjogren's syndrome, Lichen myxedematosus, and Gaucher's disease are examples of diseases associated with increased expression of immunoglobulins.
Increased expression of immunoglobulin targeted to self-proteins is a hallmark of autoimmune diseases. Autoimmune disease is a failure of the immune system to recognize auto-antigens as self. In autoimmune diseases, the immune system mistakenly attacks itself, targeting cells, tissues and organs, eventually resulting in the destruction of physiological systems. Autoimmunity and autoimmune diseases are multi-factorial in origin, with genetic predisposition, host factors (e.g. weakness of immunoregulatory controls, defects in suppressor T cells, or polyclonal stimulation of B cells resistant to controls), environmental factors and antigen-driven mechanisms being implicated in the development of autoimmunity and production of self-antibodies to self-antigens.
Gastrointestinal disorders and Systemic Lupus Erythrematosus (SLE) are two examples of autoimmune diseases. Inflammatory bowel disease (IBD), a subgroup of gastrointestinal disorders, is a group of incurable disorders that affect approximately 4 million individuals worldwide. The etiology of recurrent inflammatory bowel disease is currently unknown. Theories include an autoimmune-mediated destruction of gastrointestinal cells, including lymphocytes. Abnormal homotypic aggregation in heritable inflammatory bowel disease models has been demonstrated previously, and mutations in NOD2, a gene implicated in autoimmune disorders, has been shown to predispose patients to Crohn's disease. Ni, J. et al., Immunological abnormality in C3H/HeJ mice with heritable inflammatory bowel disease, Cell Immunol. 169:7-15 (1996); Ogura, Y. et al., A frameshift mutation in NOD2 associated with susceptibility to Crohn's Disease, Nature 411: 603-606 (2001).
IBDs most often affect the small intestine and colon, but may involve any portion of the gastrointestinal tract. There are over 1 million people diagnosed with IBD in the United States alone, with over 10,000 new cases diagnosed annually. Because of the drastic effect in the quality of life for IBD patients, tens of thousands of lost hours are claimed annually, equaling up to 1 billion dollars in missed work days a year.
IBD produces a range of gastrointestinal and extraintestinal symptoms, including diarrhea, rectal bleeding, abdominal pain, weight loss, skin and eye disorders, and delayed growth and sexual maturation in children. Two types of IBD are ulcerative colitis and Crohn's disease, which share similar symptoms and physiological manifestations, but differ in the manner in which they affect the digestive tract. Ulcerative colitis is characterized by ulcerative inflammation of all or part of the colonic mucosa, most frequently including the rectum. Its symptoms include rectal bleeding and urgency, tenesmus, and diarrhea. Ulcerative colitis is accompanied by serious short- and long-term complications. The most serious short-term complications are fulminant colitis, toxic megacolon, and perforation. Severe long-term complications include osteoporosis and colorectal cancer.
Crohn's disease is a chronic transmural inflammation that may affect any part of the gastrointestinal tract, from the mouth to the anus. Crohn's disease is discontinuous, with unaffected areas interspersed between one or more involved areas. Late in the disease, the mucosa develops a cobblestone appearance, which results from deep longitudinal ulcerations interlaced with intervening normal mucosa.
Most Crohn's disease patients present with symptoms of abdominal pain and tenderness, chronic or nocturnal diarrhea, rectal bleeding, weight loss, and fever. Crohn's disease evolves over time from a primarily inflammatory disease into one of two clinical patterns: structuring (obstructive) or penetrating (fistulizing). In the structuring form, transmural inflammation produces fibromuscular proliferation in the intestinal wall, followed by luminal narrowing. Symptoms of obstruction become common as CD progresses. In the penetrating form, sinus tracts form as inflammation tunnels through the bowel wall and breaches the serosal surface, fistulizing into adjoining tissues and even through the skin.
Ulcerative colitis and Crohn's disease are generally diagnosed using clinical, endoscopic, and histologic criteria. However, so far the traditional diagnostic techniques have established that no single finding is absolutely diagnostic for one disease or the other. Furthermore, approximately 20% of patients have a clinical picture that falls between Crohn's disease and ulcerative colitis. Patients that fit this profile are said to have indeterminate colitis.
IBD symptoms can greatly impact a patient's well-being, quality of life, and capacity to function. Inflammatory periods are protracted and frequent, and depending on the severity, life crippling. Because IBD is chronic and typically has an onset before 30 years of age, patients generally require lifelong treatment. The elucidation of a role for novel proteins and compounds in disease states for identification of potential targets and diagnostic markers is valuable for improving the current treatment of inflammatory bowel disease patients.
SLE is characterized by the production of auto-antibodies to a variety of ubiquitous molecules, which can have pathogenic consequences including damage to numerous organs and tissues, including skin, kidney, brain, and heart. The current approved treatments for SLE involve non-specific immunosuppression and symptom control through steroids, immunosuppressive drugs, immunomodulators, and anti-malarial drugs. However, these treatment approaches result in risks of renal toxicity and early mortality. Thus, it is desirable to develop a new approach that specifically interferes with lymphocyte activation and auto-antibody production.
Other autoimmune diseases in which increased expression of immunoglobulin and/or B cells play a significant role include idiopathic thrombocytopenia, rheumatoid arthritis (RA), autoimmune hemolytic anemia, and Myasthenia gravis. Evidence for the role of B cells and/or increased immunoglobulin comes from studies with patients treated with steroids, immunosuppressive agents, and/or anti-CD20 antibodies (which target B cells). Improvement in symptoms in these diseases correlates with a decrease in B cells and/or serum immunoglobulin, underscoring the pivotal role that B cells play in a variety of autoimmune diseases.
Increased expression of immunoglobulin can also be seen in malignant diseases. Like autoimmune disorders, the etiology of cancer is similarly multi-factorial in origin. Cancer, which is the second leading cause of death in the United States, has been linked to mutations in DNA that cause unrestrained growth of cells. Genetic predisposition plays a large role in the development of many cancers, combined with environmental factors, such as smoking and chemical mutagenesis.
Cancer can occur in any tissue or organ of the body. Plasma cell neoplasms, including multiple myeloma, “Solitary” myeloma of bone, extramedullary plasmacytoma, plasma cell leukemia, macroglobulinemia (including Waldenstrom's macroglobulinemia), heavy-chain disease, primary amyloidosis, monoclonal gammopathy of unknown significance (MGUS) are associated with increased expression of immunoglobulins. Chronic lymphocytic leukemia (CLL), a non-plasma cell neoplasm, is also associated with high levels of immunoglobulin expression.
Myelomas, or Kahler's disease, are tumors of plasma cells derived from a single clone, which typically originates in secondary lymphoid tissue and then migrates into and resides in bone marrow tissue. Myelomas commonly affect the bone marrow and adjacent bone structures, with primary symptoms of bone pain and pathological fractures or lesions (osteolytic bone lesions), abnormal bleeding, anemia and increased susceptibility to infections. Advanced stages of the disease include renal failure, skeletal deformities, compaction of the spinal cord, and hypercalcemia. Myeloma affects bone cells by inducing osteoclast resorption of bone, hence decimating bone structure and increasing calcium concentration in plasma. The etiology of myelomas is currently unknown. Linkage to radiation damage, mutations in oncogenes, familial causes and abnormal IL6 expression have been postulated.
Multiple myelomas are plasma cell tumors with multiple origins. Multiple myelomas account for nearly 10% of all plasma cell malignancies, and are the most common bone tumor cancer in adults, with an annual incident rate of 3 to 4 cases per 100,000 people. In the United States, multiple myelomas are the second most common hematologic malignancy after Non-Hodgkin's Lymphoma, with approximately 50,000 cases in the United States alone, and approximately 13,500 new reported cases every year. The prognosis outlook for patients diagnosed with multiple myelomas is grim, with only several months to a year for patients with advanced forms of the disease.
Traditional treatment regions for myeloma and multiple myelomas (henceforth referred to as “myeloma”) consist of chemotherapy, radiation therapy, and surgery. In addition, bone marrow transplantation is recommended for patients who are otherwise in good health. The cure rate for patients approaches 30%, and is the only method known that can cure myelomas. However, for individuals who are older or cannot tolerate bone marrow transplantation procedures, chemotherapy is most appropriate.
Current diagnostic procedures include X rays, bone marrow aspiration, blood and urine tests (to detect the presence of the Bence Jones protein), and the erythrocyte sedimentation rate assay. Potential cell surface markers in myelomatous plasma cells have also been identified, including CD38, CD9, CD10, HLA-DR, and CD20. Ruiz-Arugelles G J and San Miguel J F, Cell Surface Markers in Multiple Myeloma, Mayo Clin. Proc. 69:684-90 (1994). Other non-B-cell lineage markers include CD2, CD4, CD13, CD14, CD15, CD23, CD 24, CD25, CD33, CD39, CDw40, CD41, CD45R, CD54, CD56 and CD71, as well as unclustered antigens, R1-3, PCA-1, PCA-2, PC1, 62B1, 8A, 8F6 and MM4). Ruiz-Arugelles, supra; Leo R, et al., Multiparameter analysis of normal and malignant human plasma cells, Ann. Hematol. 64:132-9 (1992). In addition, appearance of abnormal antibodies, known as M-protein, is an indicator of multiple myeloma. The increased production of M-protein has been linked to hyperviscosity syndrome in multiple myelomas, causing debilitating side effects, including fatigue, headaches, shortness of breath, mental confusion, chest pain, kidney damage and failure, vision problems and Raynaud's phenomenon (poor blood circulation, particularly fingers, toes, nose and ears). Cryoglobulinemia occurs when M-protein in the blood forms particles under cold conditions. These particles can block small blood vessels and cause pain and numbness in the toes, fingers, and other extremities during cold weather. Prognostic indicators, such as chromosomal deletions, elevated levels of beta-2 microglobulin, serum creatinine levels and IgA isotyping have also been studied. Tricot G, et al., Poor prognosis in Multiple Myeloma, Blood 86:4250-2 (1995).
CS1 (SLAMF7, 19A; Genbank Accession Number NM—021181.3, Ref. Boles and Mathew (2001) Immunogenetics 52:302-307; Bouchon et al., (2001) J. Immunol. 167:5517-5521; Murphy et al., (2002) Biochem. J. 361:431-436) is a member of the CD2 subset of the immunoglobulin superfamily. Molecules of the CD2 family are involved in a broad range of immunomodulatory functions, such as co-activation, proliferation differentiation, and adhesion of lymphocytes, as well as immunoglobulin secretion, cytokine production, and NK cell cytotoxicity. Several members of the CD2 family, such as CD2, CD58, and CD150, play a role or have been proposed to play a role in a number of autoimmune and inflammatory diseases, such as psoriasis, rheumatoid arthritis, and multiple sclerosis.
CS1 (also known as CRACC, 19A, APEX-1, and FOAP12) was isolated and cloned by Boles, K. et al. (see Immunogenetics 52: 302-307 (2001)). It has been reported that CS1 plays a role in NK cell-mediated cytotoxicity and lymphocyte adhesion (Bouchon, A., et al., J. of Immuno. 5517-5521 (2001); Murphy, J. et al., Biochem. J. 361: 431-436 (2002)).
PCT Application PCT/US00/34963 discloses a monoclonal antibody against APEX-1 and the use thereof for detecting the produced recombinant extracellular domain of APEX-1. However, antibodies capable of inhibiting immunoglobulin production by B cells and/or proliferation and/or development of myelomas have not been developed and disclosed in the above-referenced publications. Also, evidence of over-expression of CS-1 in autoimmune disease or cancer has not been developed or disclosed in the above-referenced publications.